Improvement in head-blocks fob saw-mills



N. JOHNSON. HEAD BLOCK FOR SAWMILLS.

Patented Aug 4,1868.

NELsoN JoHNsoN, .IOEJASYPEVR, NEW YORK,

Letters Patent No. 80,632, dated August 4, 1868;

IMPROVEMENT IN HEAD-BLOCKS FOB SAW-MILLS.

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To ALL WHOM IT MAY CONCERN:

Be it known that I, NELSON JOHNSON, of Jasper, in the county of Steuben, and State of New York, have invented certain new and useful Improvements in Saw-Mills; and I do hereby declare the following to be a full, clear, and exactdescription of the same, reference being bad to the accompanying drawings,iwhich are made a part of this specification. A

My invention consists- First, in the provision of eccentric longitudinal rests, which support and dog'ithe log atboth' bottom and top, the entire length of the carriage.

Second, in devices for adjustably mounting said rests.

Tl-.ird,-in devices for operating dogs fitted to slide vertically in the head-blocks or knees.

Figure 1 is a plan view of a log-carriage embodying my improvements.

Figure 2 is a side elevation.

Figure 3 is an end elevation.

Figure 3 is a detached view of a modification of the rests.

Figure 4 is a detached perspective view of onc-head-block.

Figure 5 is a detached perspective view of one of the sliding-dogs.

A.rcpresents the body of the log-carriage, which is of ordinary construction, and is'mounted on wheels, B B, which traverse respectively the tracks C C, and to the opposite ends of which carriage the ways, D D, of analogous construction, are secured.

E E are shafts, extending through the interior of the ways, and provided with crank-pulleys,F F, on their outer ends, over which the cord-or strap G passes, communicating their motion from one to the other. Eachof. these'shafts is provided with a groove its entire length, for the reception of a spline in the interior of the sliding worm -wheel H, the thread of which occupies the segmental female screw 01 in the interior of the'way.

I I are folding knees, hinged to the shafts E E on each side of the worm H, by which they are reciprocated on the ways, the extent of theirfolding-movement being limited by the projections or lips i impinging on the bottom of the thread d, in folding down and in bracing up, said projectionscomiugin contact withi-the'rib or shoulder d, the knee being held down upon the surface of the way by the pinpr belt at, which passes through the enlargement i on the side of the base of the knee. I

jj represent dogs, hinged to the stupid i in the rear end of the knee, by which the rough log is held, and I." k vertical dogs, slidingin dove-tailed grooves, 1", -in the faces of the knees, by which the log is held afterbei'ng flatted, their dove-tailed socket preventing their being turned, and thus preventing the leg from being driven either lengthwisc'or laterally, the former of whichmovcmcnts is common in other dogs, their sockets being of such a form that the 'dog may be readily turned.

These dogs are constructed, as represented in figwfi, with angular'lips, k, in the form of a double-corner chisel, which construction forms an additional meansfor preventing the endwise displacement of the log or board's.

16 are handles, by which to operate them when but little power'is needed. They may be driven into the log with a hammer, or any other suitable means maybe employed, one being represented in fig. 4, and described hereafter.

LL are eccentric longitudinal rests, for dogging the log both at bottom and top, or on either bottom or top, asdesired, the upper one of which, L, is journalled in vertiealslots, 2"", which allow it to accommodate itself to difi'erent sizes and tapers of logs, and is operated by. the spring-lever, m, which is held by the ratchet-rack, n, on the side of the knee 1', and the lower one is journalled at z" and i, and is operated by the lever 0, which is held by the ratchet-rack p on the side of the knee I.

These rests are provided with a fiat side,l, which, when in use, is flush with the face ofthe knees, and havealso dogs Z, which are driven into the log'to hold it. 7

These dogs are set at such an angle to' the face of the rest that any endwiso pressure or the saw serves to force the log or boardagainst the face of the rest and hold it more firmly. The rests may, if desired, be made hollow, as shown in fig; 3, but should in all cases have a flat surface, against which the log may rest. They may be used assoon as the logis flatted, but are most useful when the log is'reduced to one or two boards, when they serve to prevent the boards being warped or twisted by the action of the saw.

One mode of operating the sliding-dogs is shown in fig. 4, inwhich thedog 1 is connected by a link, 2, to the pawl-lever .3, which engages with the ratchet-rack 4 on the rear face of the standard 5 of the knee, to press down the dog into the log. Thebase, 6, of the knee is slotted at 7 for the passage of the bar or shank 8, to the lower end of which the friction-rollers, 9, are attached.

These rollers bear-against the under face of. the guide-way, one on each side of the slot, their pressure being regulated by the wedge 8" which passes'through an oblong slot in the upper end of the shank.

The base is also provided at its heel with a. vertically-slotted box, 6", in which the shaft of the frictionrollers 9 is journalled. These rollers bear on the top of the way, and, together with the under rollers 9, by

reducing the friction, serve to lessen the strain on the knee, and the power required for setting the log.

Any wear on the box or shaft, or of thejournals in-the rollers 9, maybe compensated for by introducing additional plates above the shaft in the box, so as to keep the bearing-surface of the rollers slightly below the bottom of the base of the knee. M

When it is necessary to wedge out either end of a log to regulate the thickness of-the slabs-taken ofl in squaring, the sliding-dogs maybe removed and wedges inserted in their grooves, as shown in blue lines in figs. 1 and 3.

Having described my invention, ivhat I claim therein as new, and desire to secure by Lettersv Patent, is-- Q 1. The eccentric longitudinal rests L L, either or both, when constructed witha fiat fall I. and dogs I, and

operating substantially as described, for thepurpose specified.

2. The vertical slots i when employed in combination with the upper longitudinal rest- L, for the purpose of renderingsaid rest adjustable to suit different sizes and taper of logs, substantially as described.

3. The combination of the levers 3, ratchet-rack 4, link 2, and vertically-sliding dog 1, with the standard 5, substantially as and for the purpose specified.

To the above specification of my new and useful improvement in saw-mills, I have signed my hand, this I 15th day of July, A. D. 1867.

NELSON JOHNSON. Witnesses J. E. M. Bowen, Oomvms KNIGHT. 

